1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a technique which enhances strength and visibility of a miniaturized display device used in a mobile phone or the like.
2. Description of the Related Art
With respect to a liquid crystal display device, there has been a strong demand for the reduction of a thickness of a liquid crystal display panel along with a demand for the reduction of a profile size of a set while maintaining a screen at a fixed size. To decrease the thickness of the liquid crystal display panel, after manufacturing the liquid crystal display panel, an outer side of the liquid crystal display panel is polished to decrease the thickness of the liquid crystal display panel.
The liquid crystal display device is constituted of a TFT substrate which forms pixel electrodes, TFTs and the like thereon or a color filter substrate which forms color filters thereon. A glass substrate which is served for forming the TFT substrate and the color filter substrate has a thickness thereof standardized to 0.5 mm or to 0.7 mm. It is difficult to acquire such standardized glass substrate from a market. Further, an extremely thin glass substrate gives rise to drawbacks on mechanical strength, deflection or the like in manufacturing steps thereof thus lowering a manufacturing yield rate. As a result, after forming the liquid crystal display panel using the standardized glass substrate, an outer surface of the liquid crystal display panel is polished to decrease the thickness of the liquid crystal display panel.
The reduction of the thickness of the liquid crystal display panel gives rise to a drawback on mechanical strength. That is, there exists a possibility that the liquid crystal display panel is broken when mechanical pressure is applied to a display screen of the liquid crystal display panel. To prevent such breaking of the liquid crystal display panel, as shown in FIG. 10, in assembling the liquid crystal display panel in a set such as a mobile phone, a front window (hereinafter referred to as face plate) is mounted on a screen side of the liquid crystal display panel. The face plate is usually formed larger than the color filter substrate.
To prevent the application of a force to the liquid crystal display panel when an external force is applied to the face plate, the face plate is arranged in a spaced-apart manner from the liquid crystal display panel. However, the constitution shown in FIG. 10 gives rise to a drawback that display quality is deteriorated as described later. Japanese Patent Laid-Open Hei11-174417 (patent document 1) discloses a technique which copes with the drawback attributed to the structure shown in FIG. 10, for example.